Dynamics (mechanics)

Dynamics (mechanics) is a branch of physics that studies the motion of objects and the forces that cause this motion. It is a sub-discipline of mechanics, which is itself a branch of physical sciences. Dynamics can be further divided into kinematics, which describes motion without considering its causes, and kinetics, which looks at how forces affect motion.

Overview

Dynamics is concerned with the study of forces and torques and their effect on motion, as opposed to statics, which studies forces in balance. The foundations of dynamics were laid out by Sir Isaac Newton in his laws of motion, which are still used to study the motion of objects.

Newton's laws of motion

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Illustration of Newton's laws of motion

The three laws of motion laid out by Newton form the basis of dynamics. They describe the relationship between a body and the forces acting upon it, and its motion in response to those forces.

1. First law (Law of Inertia): An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
2. Second law (Law of Acceleration): The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
3. Third law (Law of Action and Reaction): For every action, there is an equal and opposite reaction.

Applications of dynamics

Dynamics has a wide range of applications in many fields of science and engineering. For example, it is used in aerospace engineering to understand how forces affect the motion of aircraft and spacecraft. In biomechanics, it is used to study the motion of living organisms. In robotics, it is used to design and control robots.

See also

• Statics
• Kinematics
• Kinetics
• Force
• Torque
• Motion (physics)